18.4.26 ndb_waiter — Wait for MySQL Cluster to Reach a Given Status

ndb_waiter repeatedly (each 100 milliseconds)
prints out the status of all cluster data nodes until either the
cluster reaches a given status or the
--timeout limit is exceeded,
then exits. By default, it waits for the cluster to achieve
STARTED status, in which all nodes have
started and connected to the cluster. This can be overridden
using the --no-contact and
--not-started options.

The node states reported by this utility are as follows:

NO_CONTACT: The node cannot be contacted.

UNKNOWN: The node can be contacted, but
its status is not yet known. Usually, this means that the
node has received a START or
RESTART command from the management
server, but has not yet acted on it.

NOT_STARTED: The node has stopped, but
remains in contact with the cluster. This is seen when
restarting the node using the management client's
RESTART command.

STARTING: The node's
ndbd process has started, but the node
has not yet joined the cluster.

STARTED: The node is operational, and has
joined the cluster.

SHUTTING_DOWN: The node is shutting down.

SINGLE USER MODE: This is shown for all
cluster data nodes when the cluster is in single user mode.

Sample Output.
Shown here is the output from ndb_waiter
when run against a 4-node cluster in which two nodes have been
shut down and then started again manually. Duplicate reports
(indicated by “...”) are
omitted.

shell> ./ndb_waiter -c localhost
Connecting to mgmsrv at (localhost)
State node 1 STARTED
State node 2 NO_CONTACT
State node 3 STARTED
State node 4 NO_CONTACT
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 UNKNOWN
State node 3 STARTED
State node 4 NO_CONTACT
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 STARTING
State node 3 STARTED
State node 4 NO_CONTACT
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 STARTING
State node 3 STARTED
State node 4 UNKNOWN
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 STARTING
State node 3 STARTED
State node 4 STARTING
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 STARTED
State node 3 STARTED
State node 4 STARTING
Waiting for cluster enter state STARTED
...
State node 1 STARTED
State node 2 STARTED
State node 3 STARTED
State node 4 STARTED
Waiting for cluster enter state STARTED
NDBT_ProgramExit: 0 - OK

Note

If no connection string is specified, then
ndb_waiter tries to connect to a management
on localhost, and reports
Connecting to mgmsrv at (null).